Power hammer



Nov. 17, 1936. E.R. BobplNGHoUsl-z POWER HAMMER 2 Sheets-Shadi, 1

Filed Nov. 9, v1934 Nov. l?, 1936. E. R. BODDINGHOUSE POWER HAMMER Filed Nov. 9, 1954 2 sheets-sheet 2 Patented Nov. 17, 1936 POWER HAMMER Emmons R. Boddinghouse, Chicago, Ill., assignor to Gas Tool Patents Corporation, Chicago, Ill., a corporation of Delaware Application November 9, 1934, Serial No. 752,307

3 Claims.

This invention pertains in general to power hammers and is shown for illustrative purposes as embodied in a hammer of the internal combustion type disclosed in the Mould Patent No.

1,868,754. The mode of operation with respect to ignition, carburetion and starting, is substantially that described in said Mould patent. The invention resides particularly in the anvil and its mounting.

One important feature of the invention resides in a construction which enables the downward thrust of the piston return springs to be exerted against the tool guide rather than against the tool itself, thereby minimizing the strain on the springs and permitting the delivery of a more effective blow upon the tool.

In many of the prior power hammers in which the piston return springs were sup-ported on the anvils, the design of these anvils and anvil housings has been such that fragments of broken springs were often able to become lodged underneath seating surfaces of the anvils and thus introduce a danger of defective operation and fracture of the parts. My present invention eliminates this danger by an anvil design which prevents spring fragments from interfering with the proper operation of the anvil.

Other objects and advantages of the invention which are inherently possessed by it will be discussed and disclosed hereinafter.

In the drawings:l

Fig. 1 is a side elevation showing the preferred construction of a gas hammer in which these improvements are to be embodied;

Fig. 2 is a partial vertical section of such a hammer showing one improved form of anvil; and

Fig. 3 is apartial vertical section showing another form of anvil provided by this invention.

Referring further to the drawings, the hammer shown in Fig. 1 comprises a cylinder provided exteriorly with a plurality of radially disposed longitudinally exteneding fins I affording provision forthe rapid dissipationof heat generated 45 within the cylinder. Below the cylinder is an anvil housing 2 separated from the cylinder casting 3 by means of an insulating gasket 4. At the top of the ns and resting thereupon is a handle supporting member 5 and secured thereupon at opposite sides are a pair of handles, one of which, designated B, is shown. These are the handles which the operator grasps for holding the gas hammer.

Below the anvil housing 2 is a tool guide 1 which houses the upper end of a tool such as a drill 8.

The tool'guide 1 is slidably mounted on a pair of-rods 9 and II which are provided with nuts at their lower ends against which are seated compression springs I2 and I3. The upper' ends of these springs rest against shoulders as shown on the tool guide 'I. The rods 9 and YII extend upwardly through the anvil housing, seating thereagainst by means of shoulders I4 and I5 which cooperate with corresponding recesses in the anvil housing torprevent the latter from slipping downwardly on the rods. The upper ends of thes'e rods extend through the handle supporting member 5 and are secured thereupon by means of nuts I6 and I'I. Through the cooperation of the circumferential shoulders I4 and I5'and the nuts I6 and I'I the rods Sand II hold the anvil housing firmly secured against the bottom of the cylinder casting. The tool guide, however,v is free to slide upwardly and downwardly on these rods and is yieldingly held against the bottom of the 20 anvil housing by means of the springs I2 and I3. Referring particularly to Fig. 2. an anvil I8 is disposed in the anvil housing and provided with an renlarged lower end` I9, the upper shoulder of which seats against a cooperating shoulder in the anvil housing for'limiting upward movement of the anvil. 'I'he upper portion 2l of the anvil is of reduced diameter so as to provide a shoulder 22 upon which the piston returnk springs are seated. 4Preferably thev return springs consist of two springs arranged in series, the lower spring 23 being the shorter and heavier spring while the yupper spring 24y rests upon the cushion spring 23 and abuts the top of a recess 25 in the piston 26. A depending portion 21 of the piston constitutes the striking portion lof the piston which upon downward movement'of the piston induced by explosion of a combustible mixture or otherwise iscaused to impact the to-p of the anvil extension 2|. 40

Thecooperating shoulders of the anvil and its housing being separated from the piston springs by a portion of the anvil body between which and the surrounding housing sliding clearance only is provided, it will be apparent that broken piston spring particles are precluded from lodging between said shoulders and damaging the apparatus. While such spring breakage is rare, the damage occasioned by the lodgment of spring particles between the opposed shoulders of the 50 anvil and housing in apparatus permitting entrance of such spring particles has been serious. In the normal operation of the device shown in Fig. 2 the blow of the piston will ordinarily be absorbed directly through the anvil I8 upon the 55 drill 8. However, should the Idrill be lifted from the work temporarily by the operator while the hammer is running, the anvil blows will be absorbed by the tool guide I whose heavy supporting springs I2 and I3 are amply able to cushion these shocks. v

In the embodiment of the invention shown in Fig. 3, the anvil consists of an outer sleeve generally indicated as 3l and an inner striking pin 32 which has a sliding t within the sleeve. The upper end 33 of the sleeve provides the supporting seat for the piston springs. These springs may be one or more in number and in the.illus trated embodiment include a cushion spring`34 and a main return spring 35, the'latter being'dis.-A posed between the cushion spring and the op,-l

The strikingV posed surface 36 of the piston 3l. portion 38 of the piston in its working stroke imparts a blow to the striking pin 32 of the V anvil and thence to the tool 4I).

It will be noted that a shoulder 4I on the sleeve of the anvil cooperates with a corresponding shoulder on the anvil housing 42 to limit the upward movement of the anvil sleeve. This shoulder is spaced from the spring supporting shoulder 33 so that it is protected from spring fragments which would interfere with the proper seating of the anvil sleeve.

The lower edge 43 of the anvil sleeve rests directly upon the tool guide. Hence, when the explosion drives the piston downwardly and the cylinder and associated parts are simultaneously driven upwardly, the upwardmovement of the tool guide 1 and sleeve 3| is resisted 4with progressively increasing effort by the springs 34-35 as they are compressed by the piston. This resistance imposes a compression strain upon the tool guide supporting springs I2 with the result that a snubbing action against the rise of the cylinder is produced, which causes the tool to operate quieter, steadier, smoother, and more eiciently and with less Vibration transmitted to the operator. l

The down or working stroke ofV the piston necessarily compresses the return springs and in constructions of the type exemplifiedrby Fig. 2 wherein the spring force is transmitted tothe tool there existsfa tendency for this force` to impart an initial movement to the tool before it receives the impact from the piston,consequent ly the eiectiveness of the blow is somewhat deadened.

In the construction of Fig. 3 the force of the piston springs under compression is transmitted by the sleeve portion of the anvil, not to the tool but to the tool guide. The tool therefore remains in its uppermost position to receive'the full impact of the blow under whichethe most effective stroke of the tool is delivered.

Furthermore, should the strokeoftheanvil under impact thrust the lower end of the anvil piece 32 against the tool guide 'I with sufficient force to drive this guide away from the lower end of housing 42 against which it is yieldingly held by springs I2 and I3, the sleeve piece 3Iof the anvil will travel with the piece 32 and the guide I, thereby relieving the piston springs from further and undue compression which would be likely to result in breakage.

In ordinary operation the weight of the entire apparatus will be carried by the tool 40 which will push the striking piece 32 upwardly into the anvil sleeve into the position shown in Fig. 3.

Should the hammer be lifted temporarily from the work, the enlarged head 44 of the striking piece 32 will strike the tool holder 1 and the shock will then be absorbed through the compression springs such as I2 or I3.

While I have shown in the drawings and described the preferred embodiments of my invention, it is to be understood that I do not intend 'thereby to be limited to the particular forms disclosed, but aim to cover all modifications and alternative constructions falling within the spirit andscope of the invention as expressed in the appended claims.

I claim:

1. In. an impact tool of the explosive type, the combination of a cylinder, a piston hammer reciprocable therein, a housing in alignment with said cylinder, a two piece anvil in said housing comprising an impact portion aligned to receive the blow of said hammer and a surrounding sleeve, a tool guide against which the outer end of said sleeve abuts, spring means interposed between said piston hammer and the inner end of said sleeve by which driving force of said piston on its working stroke is transmitted through the intermediary of said sleeve to said tool guide, and means yieldably securing said tool guide to said housing whereby the downward piston thrust against the tool guide is caused to snub the upward thrust of the cylinder resulting from the eX- plosion in the cylinder.

2. In an impact tool of the explosive type, the

the explosion therein, said means comprising a tool guide beneath said cylinder, asleeve surrounding said anvil member and engaged at its lower end with said tool guide, a piston return spring interposed between the upper end of said sleeve and said piston and means for yieldably connecting said tool guide to said cylinder.

3. An impact tool of the explosive type comprising a cylinder and an explosion actuated impact delivery member reciprocable therein, a spring for returning the same, a tool guide, a tool guided thereby, means for transmitting the delivered impact from said member to said tool, means interposed between said spring and said tool guide for transmitting the spring thrust to said guide, and means yieldably connecting said tool guide to said cylinder whereby the thrust of the cylinder induced by the explosion is yieldingly snubbed.

EMMONS R. BODDINGHOUSE. 

